The present invention relates to a micro-adjustable displacement and rotation setting apparatus which is capable of applying extremely small amounts of linear displacement or angular rotation to a controlled member such as a workpiece-retaining jig portion of precision machining equipment.
At present, there are a large number of applications requiring apparatus which will provide very minute amounts of linear movement or rotation of a controlled member, which for example may support a workpiece which is to undergo highly precise machining, or may comprise part of an apparatus used for some type of precision measurement. Here, the term "minute" refers to linear displacements of the order of 0.005 microns or less, or angular rotations of 0.01 seconds or less. It is generally essential that such an apparatus be substantially free from backlash effects, should have a high degree of adjustment resolution, and should display excellent dynamic and static stability. In the present context, the term "stability" indicates that the apparatus should perform rapid movement of the controlled member to a new position when such a change is designated, without overshoot or oscillation, and should retain the controlled member firmly in the designated position to a high degree of accuracy irrespective of momentary loads being applied to the controlled member. Such momentary loads can occur in the course of machining a workpiece held by the controlled member, for example. The qualities referred to above are also sometimes referred to as the "stiffness" of the system. A micro-adjustable displacement and rotation setting apparatus according to the present invention meets these requirements for static and dynamic stability to a much greater extent that has been possible in the prior art, yet is basically simple and economical to manufacture. Such a micro-adjustable displacement and rotation setting apparatus will therefore prove valuable in a wide variety of applications, in the fields of machinery manufacture, precision measurement, etc.